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排序方式: 共有132条查询结果,搜索用时 97 毫秒
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2.
Paweł Wyżga Igor Veremchuk Matej Bobnar Primož Koželj Steffen Klenner Rainer Pöttgen Andreas Leithe-Jasper Roman Gumeniuk 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(23):5245-5256
The homogeneity range of ternary iron indium thiospinel at 873 K was investigated. A detailed study was focused on two distinct series (y=z): 1) a previously reported charge-balanced (In0.67+0.33y□0.33−0.33y)tetr[In2−zFez]octS4 (A1-series; □ stands for vacancy; the abbreviations “tetr” and “oct” indicate atoms occupying tetrahedral 8a and octahedral 16d sites, respectively) and 2) a new charge-unbalanced (In0.67+y□0.33−y)tetr[In2−zFez]octS4 (A2-series). Fe atoms were confirmed to exclusively occupy an octahedral position in both series. An unusual reduction of the unit cell parameter with increasing Fe content is explained by differences in the ionic radii between Fe and In, as well as by an additional electrostatic attraction originating from charge imbalance (latter only in A2-series). The studied compound is an n-type semiconductor, and its charge carrier concentration increases or decreases for larger Fe content within the A1- and A2-series, respectively. The thermal conductivity κtot is significantly reduced upon increasing vacancy concentration, whereas the change of power factor is insufficient to drastically improve the thermoelectric figure of merit. 相似文献
3.
Primo? Moravec 《Israel Journal of Mathematics》2011,185(1):189-205
In this paper we obtain bounds for the order and exponent of the Schur multiplier of a p-group of given coclass. These are further improved for p-groups of maximal class. In particular, we prove that if G is p-group of maximal class, then |H
2(G, ℤ)| < |G| and expH
2(G, ℤ) ≤ expG. The bound for the order can be improved asymptotically. 相似文献
4.
A ring is called commutative transitive if commutativity is a transitive relation on its nonzero elements. Likewise, it is weakly commutative transitive (wCT) if commutativity is a transitive relation on its noncentral elements. The main topic of this paper is to describe the structure of finite wCT rings. It is shown that every such ring is a direct sum of an indecomposable noncommutative wCT ring of prime power order,
and a commutative ring. Furthermore, finite indecomposable wCT rings are either two-by-two matrices over fields, local rings,
or basic rings with two maximal ideals. We characterize finite local rings as generalized skew polynomial rings over coefficient
Galois rings; the associated automorphisms of the Galois ring give rise to a signature of the local ring. These are then used to further describe the structure of finite local and wCT basic rings. 相似文献
5.
Mitja Krnel Primož Koželj Stanislav Vrtnik Andreja Jelen Magdalena Wencka Peter Gille Janez Dolinšek 《无机化学与普通化学杂志》2020,646(14):1099-1104
We present the anisotropic electrical and thermal transport coefficients (electrical resistivity, magnetoresistance, thermoelectric power, thermal conductivity), the magnetic properties, the specific heat and the electronic density of states of a monocrystalline In3Ni2 intermetallic compound, representing a precious-metal-free (and noble-metal-free) intermetallic catalyst for the selective hydrogenation of α,β-unsaturated aldehydes. The investigated physical parameters were determined along three orthogonal crystal-symmetry directions of the trigonal structure, the twofold axis, the 3 axis and within the mirror plane. All the investigated tensorial and vectorial quantities show the same anisotropy, with the quantities being isotropic for the twofold direction and in the mirror plane, whereas there is small, though still significant anisotropy to the 3 direction. The In3Ni2 crystal conducts the electricity and heat somewhat less efficiently along the 3 direction than along the twofold direction and in the mirror plane, but the differences are not large, of about 20 %. In3Ni2 is a diamagnetic intermetallic compound, with a presumably simple Fermi surface and electrons as the majority charge carriers. 相似文献
6.
7.
Primož Ternik 《ournal of non Newtonian Fluid Mechanics》2010,165(19-20):1400-1411
The steady flow of generalized Newtonian fluid in a two-dimensional 1:3 sudden expansion was studied numerically. Finite volume method was applied to solve the momentum equations along with the continuity equation and the Power law rheological model within the laminar flow regime for a range of Reynolds number and Power law index values. The values of generalized Reynolds number, based on physical and rheological properties, upstream channel height and bulk velocity, were varied between 0.0001 ≤ Regen ≤ 10, while the Power law index values mapped the 0.60 ≤ n ≤ 1.40 range, allowing for the investigation of both shear-thinning and shear-thickening effects at creeping as well as slowly moving fluid flow conditions. We report accurate results of a systematic study with a focus on most important characteristics of recirculating fluid flow in the downstream section of sudden expansion geometry. It is shown that for the creeping flow regime there exist finite sized redevelopment length, extra pressure drop (Couette correction) and recirculation zones (also called as Moffatt vortices) that are influenced by the non-Newtonian viscous behaviour. 相似文献
8.
Primo Emiliano N. Bracamonte María V. Luque Guillermina L. Bercoff Paula G. Leiva Ezequiel P. M. Barraco Daniel E. 《Journal of Solid State Electrochemistry》2019,23(6):1929-1938
Journal of Solid State Electrochemistry - This study presents a simple and scalable synthesis of pyrite (FeS2) starting from S and Fe powders, which involves high-energy ball milling of precursor... 相似文献
9.
Following Alspach and Parsons, a metacirculant graph is a graph admitting a transitive group generated by two automorphisms ρ and σ, where ρ is (m,n)-semiregular for some integers m≥1, n≥2, and where σ normalizes ρ, cyclically permuting the orbits of ρ in such a way that σ
m
has at least one fixed vertex. A half-arc-transitive graph is a vertex- and edge- but not arc-transitive graph. In this article quartic half-arc-transitive metacirculants are explored
and their connection to the so called tightly attached quartic half-arc-transitive graphs is explored. It is shown that there
are three essentially different possibilities for a quartic half-arc-transitive metacirculant which is not tightly attached
to exist. These graphs are extensively studied and some infinite families of such graphs are constructed.
Both authors were supported in part by “ARRS – Agencija za znanost Republike Slovenije”, program no. P1-0285. 相似文献
10.
Primo? Poto?nik 《Discrete Mathematics》2006,306(1):107-123
A graph is called almost self-complementary if it is isomorphic to one of its almost complements Xc-I, where Xc denotes the complement of X and I a perfect matching (1-factor) in Xc. Almost self-complementary circulant graphs were first studied by Dobson and Šajna [Almost self-complementary circulant graphs, Discrete Math. 278 (2004) 23-44]. In this paper we investigate some of the properties and constructions of general almost self-complementary graphs. In particular, we give necessary and sufficient conditions on the order of an almost self-complementary regular graph, and construct infinite families of almost self-complementary regular graphs, almost self-complementary vertex-transitive graphs, and non-cyclically almost self-complementary circulant graphs. 相似文献